Cape Town — South African President Jacob Zuma paid a late-night visit Wednesday to the hospital where Nelson Mandela is critically ill. His office announced soon afterwards he was cancelling a trip to neighbouring Mozambique on Thursday.

These developments follow reports earlier Wednesday - unconfirmed by Zuma's office - that Mandela is on artificial life support.

Johannesburg's Citizen newspaper said it has been told by five sources close to the Mandela family - including two who have visited him - that Mandela is breathing with the help of a ventilator.

Later, Agence France-Presse reported Napilisi Mandela, a family member who had visited Mandela, as saying: "Yes, he is using machines to breathe... It is bad, but what can we do."

The South African Press Association said Zuma had arrived at the Pretoria hospital shortly before 10 pm and left at 10.15 pm.

As he was leaving, the news agency posted a government statement announcing Zuma's visit to Maputo for a Southern African Development Community infrastructure investment summit. Half an hour later, a new statement said Zuma had cancelled the trip.

"President... Zuma visited former President Nelson Mandela in hospital this evening... and found him to be still in a critical condition," the statement said.

"President Zuma was briefed by the doctors who are still doing everything they can to ensure his (Mandela's) well-being. President Zuma has decided to cancel his visit to Maputo," the presidency's statement said.